I have used TeXmacs for teaching a few times and one thing which needs improvement is the drawing tool.

In particular I have missed the following:

- Making lines longer or shorter by pulling at one end; useful for making several parallel lines of different length: copy one several times, stretch or compress the others

- Rotations in large steps (e.g. 45 or 90 degrees)

- An align/distribute tool

- A circle tool where one fixes centers and radius (there is an implementation by Max in the Forum, it would be nice to have it as standard)